In many commercial environments, it is necessary to interconnect pipe or conduit sections for temporary use, which conduit sections are subsequently disassembled, moved to another location and reassembled. Under such circumstances, it is desirable to provide means for simply and quickly interconnecting pipe or conduit sections by means of couplings that can be reused a number of times. One example of such use of pipe and pipe couplings is in the petroleum industry for the drilling of wells. Fairly large diameter conduit is typically utilized as the return line transporting drilling fluid or mud exiting from the well to suitable facilities for treating the drilling mud prior to its reuse. Such mud return lines are typically at relatively low pressure, i.e. less than 100 psi, and thus it is not necessary that a high pressure joint be established between the conduit sections. The flow lines that make up a mud return line of a typical drilling rig include a number of straight pipe sections which may be coupled together or may be coupled by 45.degree. or 90.degree. elbows. These mud return lines extend from the well drilling Christmas tree assembly to a shale separator utilizing viboratory screens that separate drill cuttings from the drilling fluid. The drilling fluid may then be subjected to a degree of centrifugal separation before being transported to mud storage and treatment pits for storage until reuse is desired. Further, in many cases, the mud pits of drilling rigs are formed by large metal vat structures, two or three or more of which are interconnected by means of sections of fairly large diameter conduit. In these mud pits, the drilling fluid is treated by means of gravity separation or settling such that drilling fluid at the last one of the pits is in cleaned and revitalized condition and ready for pumping into the well during drilling operations. Typically, additional additive materials are introduced into the drilling mud in the last pit to replace lost constituents of the drilling fluid and to accomplish any desired modifications that are appropriate to the drilling conditions that are presently being encountered.
When a drilling rig is being set up for the purpose of drilling one or more wells, the commercial advantage of the drilling operation is enhanced by any mechanism that assures minimal setup time. Likewise, the effective cost of well drilling operations is minimized if the various components of the well drilling system can be disassembled with minimal delay and effort after the well drilling operations have been concluded. It is desirable, therefore, to provide a coupling mechanism for insuring the assembly and disassembly of conduit sections with minimal labor and minimal requirement for the use of tools in the assembly or disassembly activities.
Another important consideration where pipe systems and pipe couplings are frequently assembled and disassembled, is the requirement for coupling mechanisms that incorporate minimal numbers of parts and further incorporate parts that may be assembled and disassembled a number of times without substantial deterioration. Also, it is desirable to provide pipe couplings that are assembled such that the various parts thereof cannot become inadvertently disassembled and lost as the couplings are being moved from place to place.